Semi-continuous vertical casting mould for ingots

ABSTRACT

An improved peripheral mould for the semi-continuous vertical casting of ingots, providing a compound disassembliable structure with internal fluid cooling. The mould constitutes an improvement over known art by providing a thickened casting surface to prevent thermal warpage and to allow steeply angled coolant dispersal holes which tend to provide more efficient and uniform cooling and combined with a particular input system maintain water in the mould structure upon failure of the coolant supply to prevent mould damage.

United States Patent Wagstatf et a1.

[451 Sept. 5, 1972 [54] SEMI-CONTINUOUS VERTICAL CASTING MOULD FORINGOTS [72] Inventors: Frank E. Wagstaff; William G. Wagstaff; Paul H.May, all of PO. Box 186, Spokane, Wash. 98112 [22] Filed: Dec. 20, 1971[21] Appl. No.: 209,728

[52] US. Cl .....164/283 [51] Int. Cl. ..B22d 11/12 [58] Field of Search..164/89, 283

[56] References Cited UNITED STATES PATENTS 2,414,269 l/l947 Nicholls164/89 2,515,284 7/1950 Zeigler et a1 ..164/89 3,463,220 8/1969 Moritz164/89 3,098,269 7/1963 Baier ..l64/283 Primary Examiner-J. SpencerOverholser Assistant Examiner-V. K. Rising Att0rneyKeith S. Bergman [57]ABSTRACT An improved peripheral mould for the semi-continuous verticalcasting of ingots, providing a compound disassembliable structure withinternal fluid cooling. The mould constitutes an improvement over knownart by providing a thickened casting surface to prevent thermal warpageand to allow steeply angled coolant dispersal holes which tend toprovide more efficient and uniform cooling and combined with aparticular input system maintain water in the mould structure uponfailure of the coolant supply to prevent mould damage.

4 Claims, 5 Drawing Figures PKIE'N'IEMEF smz v 3.688.834

sum 2 or 2 FRANK 5 WAGSTAFF, W/LL/AM a. WAGSMFF and Rs PAUL H MA),

SEMI-CONTINUOUS VERTICAL CASTING MOULD FOR INGOTS II. BACKGROUND OFINVENTION IIA. RELATED APPLICATIONS There are no applications directlyrelated hereto now filed in any foreign countries but this inventiondoes constitute an improvement over the general type of mould disclosedin our co-pending application Ser. No. 599,444, filed July 30, 1970 forContinuous Casting Mould.

IIB. FIELD OF INVENTION This invention relates generally to the field ofperipheral, vertical casting moulds having fluid cooling through aninternal chamber and more particularly to such moulds providing maximumheat transfer area and thermal stability.

IIC. DESCRIPTION OF PRIOR ART Metallic ingots, particularly of aluminum,have heretofore been cast in a semi-continuous vertical process by usinga peripheral mould defining a horizontal cross-section of the ingot. Themoulds, of necessity, are cooled, generally by water circulating throughan internal chamber to thereafter impinge upon the ingot surfaceemerging from the mould to additionally aid solidification of the castingot. The general nature of such moulds is well known in the prior artand particular forms are set forth in our prior application heretoforereferred to.

The form of such moulds has become somewhat standardized by reason ofmanufacturing practice and the vparticular necessities of an internalsurface defining in a horizontal plane the periphery of the ingot to becast. The moulds vertical extension is somewhat limited to alleviatesticking of the cast ingot after solidification of its surface, andallow immediate impingement of coolant to prevent undesirably physicalchanges in the ingot. Normally the interior of the mould is divided intotwo adjacent, concentric annular chambers-the outer chamber serving as amanifold for cooling fluid to disperse it through a dividing septum intoan inner dispersal chamber where it serves its primary cooling functionand from whence it is dispersed downwardly and inwardly to impinge uponthe emerging moulded ingot surface to aid solidification of the castmaterial. The details of construction of such mould may varyconsiderably, but to this extent they are essentially similar.

In using such moulds various problems have been experienced which theinstant invention seeks to remedy:

With use, the mould configuration tends to skew and its individualelements tend to warp, apparently largely by reason of semi-plastic flowof the mould material and internal stresses and strains caused by thethermal activities of the moulding process. If the skewing and warpagebe not great, they sometimes may be corrected by bending and additionalfinishing, though if this be accomplished the life of the mouldthereafter is not great. The instant invention seeks to alleviate thisproblem of change in mould configuration by providing a thicker inner ormoulding surface. This thicker surface cooperating with the other mouldparts prevents skewage by reason of its beam effect and prevents warpageapparently by faster, more efficient heat transfer which preventscrystalline structure change, plastic flow or similar problems.

The thicker interior casting wall also permits a more acute angling offluid output channels to allow them to enter the upper portion of theinner water chamber and present a greater surface area for contact ofmould and coolant which tends to provide a more efficient heat transferfor more efficient and uniform cooling of both mould and ingot.

In moulds of the prior art, problems of overheating upon interruption ofcoolant flow-have been common since the inner cooling chamber normallyexhausts through fluid exit channels located in the lower portion of thechamber, so that if coolant flow be interrupted to the mould, the fluidin the inner chamber immediately drains to allow a possible overheatingof the mould in the period of time necessary to correct or alleviate theproblem. The instant invention provides the communication of fluid exitchannels in the upper portion of the inner fluid chamber so that theinner chamber may not be drained by water flowing through the exitchannels. Coolant level in the mould will therefore be at least at thelevel of the imput and if coolant cannot reverseflow through the imputchannel; the coolant level may be above the imput level so that theinner cooling chamber will retain coolant upon imput failure and preventoverheating for some period to allow a reaction time to correct flowagedifficulty or allow shutdown before damage is done to the mould.

III. SUMMARY OF INVENTION Our mould is of annular shape providing avertical internal moulding surface defining the periphery of an ingot tobe cast and having some outward extension to define an annular coolantchamber outwardly adjacent the moulding surface. The lowermostinwardlyfacing portion of the mould is provided with an annular coolantdispersal skirt communicating by plural spaced holes angling inwardlyand upwardly to communicate with the inner surface of the water chamberin its upper part. The mould is formed with a separate releasably joinedbottom element to allow for manufacturing and access to the coolantchamber for necessary cleaning. The annular coolant chamber is dividedby a medial septum into an inner dispersal chamber and an outer,surrounding, manifold chamber with plural holes communicating throughthe septum to allow flow from the manifold to the coolant chamber. Theseptum itself is preferably mechanically joined to the bottom element sothat it may be removed therewith to aid cleaning and its upper portionis provided with an appropriate gasket to provide a seal requiringcoolant flowing from the manifold chamber to pass through the septumholes to enter the dispersal chamber.

An externally communicating orifice with associated fixture is providedto allow the input of pressurized fluid coolant into the manifoldportion of the coolant chamber.

In providing such a mechanism it is:

A principal object of our invention to create a peripheral verticalcasting mould having a substantially thickened inner casting surface toprevent mould warpage and skewage and extend the useful life of themould.

A further object of our invention to provide such a mould with coolantexhaust channels communicating from an annular skirt in the lower innerportion of the mould upwardly and outwardly to the upper portion of thecoolant chamber to maintain the coolant chamber full of fluid uponinterruption of coolant flow.

A still further object of our invention to provide relatively smallexhaust channels of relatively great surface area to increase thevelocity of coolant flow therethrough to aid heat transfer and theefficiency of cooling, especially by disturbing steam formationimmediately adjacent the channel defining mould walls.

A still further object of our invention to provide a mould that is ofnew, novel and improved design, of rugged and durable nature, of simpleand economic manufacture and otherwise well adapted to the uses andpurposes for which it is intended.

Other and further objects of our invention will appear from thefollowing specification and accompanying drawings which form a parthereof. In carrying out the objects of our invention, however, it is tobe remembered that its essential features are susceptible of change indesign and structural arrangement with only one preferred and practicalembodiment being illustrated in the accompanying drawings as required.

IV. BRIEF DESCRIPTION OF DRAWINGS In the accompanying drawings whichform a part of this application and wherein like numbers of referencerefer to similar parts throughout:

FIG. 1 is an isometrical surface view of a typical peripheral castingmould embodying the improvements of our invention.

FIG. 2 is a vertical cross-sectional view through the end part of themould of FIG. 1 taken on the line 22 thereon in the direction indicatedby the arrows.

FIG. 3 is a vertical cross-sectional view through the side of the mouldof FIG. 1 taken on the line 3-3 thereon in the direction indicated bythe arrows to show water level in the internal coolant chamber uponinterruption of fluid flow.

FIG. 4 is an isometric view of a sectional piece of our mould showingthe details of its construction.

FIG. 5 is an exploded isometric view of our invention showing the natureand relationship of its various elements.

V. DESCRIPTION OF THE PREFERRED EMBODIMENT The bottom opening mouldstructure of the drawings comprises upper moulding element and bottomelement 11 releasably joined by fastening means 12 to define internalcoolant chamber 13 divided into outer manifold chamber 36 and innerdispersal chamber 37 by septum 14.

Upper mould element 10 provides annular body 15 defining the verticalinternal mould periphery by inner surface 16 of moulding wall 17. Theelement is generally milled from unitary metallic stock to defineinternal coolant chamber 13 in such fashion that the thickness ofmoulding wall 17 is quite substantial, approximating 1 inch in thicknessnormal to the moulding surface when the other body parts are configuredas in the illustrations of FIGS. 2 and 3. This provides in the body aU-shaped beam-like structure that is especially resistant to skewingforces. Outwardly projecting lip 18 is provided for mounting the mouldon a horizontal support in the fashion tradionally employed in presentday ingot casting. The lower, inner portion of moulding wall 17 definescoolant dispersal skirt 19, configured to aid the flow of coolant fluidthereover to substantially uniformly impinge upon the peripheral surfaceof an exiting ingot to aid cooling of the cast product. The lower innerportion of moulding wall 17 is removed to form bottom ledge 20 adaptedto receive the outer periphery of the bottom element.

Plural spaced dispersal channels 21 communicate from outer orifices 22in the outer portion of bottom ledge 20 upwardly and inwardly to innerorifices 23 spaced along the upper inner surface of moulding wall 17 tocommunicate with the dispersal chamber. Normally the dispersal channelswill be separated by some distance to provide webs of substantialdimension to cause sufficient rigidity in the lower portion of mouldingwall 17 to prevent warping, especially such as would allow an unevenflow of coolant to cause a further skewing of mould or ingot accordingto the prior art and teachings of our prior patent applicationhereinbefore referred to. The relative size of the dispersal channelsmust be determined by known methods to provide appropriate cooling andallow exit of the input coolant with some velocity, preferablysufficient to disturb or destroy steam effects on the surface of thedispersal channel-defining walls to provide more efficient heat transferand consequent cooling of the mould structure. The dispersal channelswill normally be symmetrically and equally spaced to providesubstantially equal cooling throughout the mould and to provide asubstantially uniform curtain of coolant impinging upon the exitingingot so that the cooling will be symmetrical and not cause skewing ofmould or ingot or either in relation to the other. Corners may requiresome deviation from equal spacing but such corner distributions ofcoolant channels are known in the prior art.

Bottom element 11 is a flat annular structure of cross-sectionalconfiguration illustrated in FIG. 2, et seq. It provides an upper innersurface adapted to fit against the lower surface of bottom ledge 20 andis of an appropriate configuration to extend about the entire bottomsurface of the annular mould to enclose the coolant chamber. Medialannular septum groove 24 is provided to receive the lower edge of theseptum and outer annular gasket groove 25 is provided to receivering-type gasket 26 in appropriate position to seal the upper surface ofbottom element 11 against the lower surface of the outer portion ofupper element 10 in a water-tight joinder. Outwardly facing surface 27of the bottom member is angled, as illustrated in the crosssectionalviews of FIGS. 2 and 3, to cooperate with the adjacent lower surfaces ofthe lower portion of bottom ledge 20 and skirt 19 to form coolantdispersing annulus or skirt 28 to substantially uniformly dispersecoolant received from the plural dispersal channels upon the emergingsurface of a cast ingot.

Fastening means 12 in this instance comprises headed bolts 29,communicating through plural spaced holes 30 in the bottom element tothreadedly engage within plural cooperating threaded holes 31 in thelower portion of the upper element to releasably join the members, againas illustrated in the sectional diagrams of FIGS. 2 and 3. Othermechanical fastening means might serve a similar purpose, and pins havebeen used in similar moulds for commerce.

Septum 14 is formed from annular band-like element 32 of materialsufficiently flexible to fit in its lower portion within septum groove24 in bottom element 11. The joint between these members issubstantially water tight and mechanically maintained by swagihg orother fastening means. The upper portion of element 32 carries gasket 33fitting about the upper edge of the septum by means of groove 34. Thevertical dimensioning of the septum and gasket are such that whenpositioned as illustrated in the cross-sections of FIGS. 2 and 3, theseptum will divide internal coolant chamber 13 into outer manifoldchamber 36 and inner dispersal chamber 37. The lower medial part of theseptum is provided with a row of holes 35 at spaced distance from eachother and from the lower edge of the septum. These holes 35 allow accessof coolant from outer chamber 36 into inner chamber 37 from whence itmight be dispersed through the dispersal channels. The number of holesand their size may vary according to known standards in the art to allowan appropriate flow of water to maintain the inner dispersal chamber 37full and provide appropriate pressure of the fluid coolant through thedispersal channels to prevent formation of gas on the channel walls andprovide an efficient cooling for the mould and emerging ingot.Preferably the holes are smaller than the dispersal channels to act as astrainer for debris because they are easier to clean than the dispersalchannels.

Coolant fluid is supplied to outer manifold chamber 36 through inputfixture 38 and input piping 39 from some external pressurized source notshown).

The use of our casting mould is substantially the same as that ofsimilar moulds heretofore known. The function of the improvements,however, is to be particularly noted.

The thickened structure of moulding walls 17 prevents premature warpageand substantially prolongs the life of the mould. The instant mould isparticularly adapted for use in the aluminum industry where such mouldsare traditionally machined from cast aluminum stock. The reason thatthis mould does not warp and that its life is prolonged is notdefinitely known, but most probably the thicker wall accompanied by theparticular position and configuration of dispersal channels provides amore uniform and more efficient transfer of heat through and away fromthe moulding surface which apparently substantially lessens or preventsdeleterious changes in the structure of the mould material, especiallyby way of re-crystallization and semi-plastic flow. Heat distributionthroughout the gross mass of the mould apparently is also more uniformto prevent deleterious changes in various parts of the mould caused bydifferential thermal gradients.

The condition of coolant in the mould upon stoppage of flow from theinput source is illustrated in FIG. 3 of the drawings. With innerorifices 23 of the dispersal channels 21 in the upper portion of theinner surface of moulding wall 17, when coolant ceases to flow from theinput source it will assume a level not below the lowermost surface ofeither the input orifice or dispersal channel orifice. lf fluid may notreturn through the input channel the level may be above the inputorifice. Since either orifice is in the upper portion of the innerdispersal chamber, a substantial level of coolant will remain in theinner dispersal chamber upon any failure of pressurized input. Thiscoolant will tend to provide additional cooling for the mould forsometime after failure of coolant input and this period of time will besufficient to correct an accidental problem interrupting the flow toprevent damage to the mould during the casting process or allow stoppageof the moulding process. The moulds heretofore known generally had anorifice located near the bottom portion of the coolant chamber whichallowed fluid to exit therefrom upon failure of the pressurized input.

It is further to be noted that the heavier structure of the mouldingwall of our mould and beam-like character of the mould in general tendto aid in preventing or. lessening any skewing of the mould by physicalstresses or strain.

It is further to be noted that if some of the holes in the septum becomeplugged with debris, the input chamber will tend to act as a manifold totend to equalize flow through the remaining holes to maintain coolantsupply.

The foregoing description of our invention is necessarily of a detailednature so that a specific embodiment of it might be set forth asrequired, but it is to be understood that various modifications ofdetail, rearrangement and multiplication of parts may be resorted towithout departing from its spirit, essence, or scope.

Having thusly described our invention, what we desire to protect byLetters Patent, and

What we claim is:

1. In a compound, bottom opening, liquid cooled mould for verticalsemi-continuous casting, of the class having an annular body, with avertical inner surface defining the vertical periphery of an ingot to becast and an internal annular coolant chamber separated into an outermanifold chamber and an inwardly adjacent dispersal chamber by anannular band-like septum carried by an annular bottom element releasablyjoined to the body to enclose the water chamber, the sides of theannular bottom element cooperating with the body element to form anannular dispersal skirt to impinge coolant upon the surface of anemerging ingot, the invention comprising:

a relatively thickened moulding wall defining the periphery of the ingotto be cast with plural, relatively small, spaced coolant dispersalchannels communicating from the annular dispersal skirt upwardly andinwardly with input orifices in the upper portion of the inner surfaceof the moulding wall defining the dispersal chamber.

2. The invention of claim 1 further characterized by plural spaced holesin the lower portion of the septum to allow fluid communicating betweenouter manifold chamber and inner dispersal chamber only therethrough,said holes being smaller in cross-section than the dispersal channels.

3. A compound, bottom opening, liquid mould for vertical semi-continuouscasting of metals, comprising in combination:

an annular body element having a vertical inner surface defining theperiphery of an ingot to be cast, the body having some size to partiallydefine therein the top and sides of a water chamber and the lowermostinner portion thereof aiding in defining a coolant dispersal skirt tocause coolant to impinge upon the skirt surface of an ingot being cast;

a flat annular bottom element releasably positionable upon the bodyelement to enclose the coolant chamber and having an outward edgecooperating with the body member to define an annular coolant dispersalskirt to direct coolant upon the exiting surface of an ingot, andcarrying;

a band-like septum extending upwardly from the bottom member tocommunicate with the upper surface of the coolant chamber to divide thecoolant chamber into an outer manifold chamber and an immediatelyinwardly adjacent dispersal chamber, the septum having plural spacedholes in the lower cross-section than the dispersal channels to act as'a filter therefore.

* l I I t

1. In a compound, bottom opening, liquid cooled mould for verticalsemi-continuous casting, of the class having an annular body, with avertical inner surface defining the vertical periphery of an ingot to becast and an internal annular coolant chamber separated into an outermanifold chamber and an inwardly adjacent dispersal chamber by anannular band-like septum carried by an annular bottom element releasablyjoined to the body to enclose the water chamber, the sides of theannular bottom element cooperating with the body element to form anannular dispersal skirt to impinge coolant upon the surface of anemerging ingot, the invention comprising: a relatively thickenedmoulding wall defining the periphery of the ingot to be cast withplural, relatively small, spaced coolant dispersal channelscommunicating from the annular dispersal skirt upwardly and inwardlywith input orifices in the upper portion of the inner surface of themoulding wall defining the dispersal chamber.
 2. The invention of claim1 further characterized by plural spaced holes in the lower portion ofthe sEptum to allow fluid communicating between outer manifold chamberand inner dispersal chamber only therethrough, said holes being smallerin cross-section than the dispersal channels.
 3. A compound, bottomopening, liquid mould for vertical semi-continuous casting of metals,comprising in combination: an annular body element having a verticalinner surface defining the periphery of an ingot to be cast, the bodyhaving some size to partially define therein the top and sides of awater chamber and the lowermost inner portion thereof aiding in defininga coolant dispersal skirt to cause coolant to impinge upon the skirtsurface of an ingot being cast; a flat annular bottom element releasablypositionable upon the body element to enclose the coolant chamber andhaving an outward edge cooperating with the body member to define anannular coolant dispersal skirt to direct coolant upon the exitingsurface of an ingot, and carrying; a band-like septum extending upwardlyfrom the bottom member to communicate with the upper surface of thecoolant chamber to divide the coolant chamber into an outer manifoldchamber and an immediately inwardly adjacent dispersal chamber, theseptum having plural spaced holes in the lower portion thereof forpassage of fluid from manifold chamber to dispersal chamber; a pluralityof relatively small, spaced coolant dispersal channels communicatingfrom the coolant dispersal skirt upwardly and inwardly to communicatewith the upper portion of the coolant dispersal chamber; means ofreleasably fastening the bottom element to the body element; and meansof supplying pressurized coolant fluid to the manifold chamber.
 4. Theinvention of claim 3 further characterized by: the plural spaced holesin the septum being smaller in cross-section than the dispersal channelsto act as a filter therefore.